To answer this, we will look into six lines of testimony that begin with the letter E. These steps can be applied to validate any type of historical document.

Early testimony – most if not all the new testament scripture is written before the year 78 AD. Having these documents written so close to the recorded death and resurrection of Jesus and during the life of the apostles helps prove that these documents were authentic.

Eyewitness Testimony – between the Gospel of John and the book of Acts, there are about 140 accounted details documented from eyewitnesses. These details were either written by the apostles themselves or by people who they knew were eyewitnesses. Having eyewitness testimonies is an essential component of any historical evidence.

Embarrassing testimony – there are so many embarrassing details recorded in the Bible, which you would not expect the writers themselves to have made up like for example;

• The Pharisees calling Jesus called Satan. 
• Peter denying Jesus 3 times when questioned if he knew who Jesus was.
• The disciples running into hiding while the women were the brave ones during the crucifixion.
• Having women as the first to witnesses the resurrection while the disciples were doubting that Jesus would even rise from the dead.

Having embarrassing details such as these adds to the historical evidence and helps confirm that the story of the Gospel is not made up.

Excruciating testimony – the New Testament writers died brutal/agonizing deaths when they could have saved themselves by just saying that Jesus had not risen from the dead. But they went to their deaths anyway because they could not deny the truth that they had witnessed.

Expected testimony – Prophesies mentioned in the Old Testament tell us to expect a Messiah with the same characteristics as Jesus. The book of Isaiah in Chapter 53 has one of the famous prophetic chapters. This book was written approximately 600 years before Jesus was even born. Check it out for yourself. 

Extra-biblical testimony – even if you disregard all the manuscripts that make up the New Testament, there are about ten other authentic ancient non-Christian sources available. These sources are written within 150 years of Jesus’s life (documenting His storyline and the early church). Using them alone, you could draft up the entire New Testament.